Adjustable piston valve damper

Abstract

An adjustable damper is provided with a variable electrically controlled damping rate being effected through the use of a sliding spool control valve carried on the piston in cooperation with a passive damping valve also carried on the piston to provide a compact and unitized assembly. Damping fluid flow through the piston passes through both the control valve and the passive damping valve.

What is claimed is: 
     
       1. An adjustable damper comprising: a tube;   a piston slidably carried within the tube;   a damping valve carried on the piston;   a control valve carried on the piston including a slidable valve spool carried in a bore wherein a damping level provided by the piston is adjustable in response to selective sliding of the spool wherein the spool includes a first end and a second end and further comprising a first coil positioned at the bore near the first end and a second coil positioned at the bore near the second end wherein the piston includes a body with a top surface and a bottom surface and wherein the damping valve is a single annular bi-directional valve disc and is carried adjacent the top surface of the piston body and wherein the control valve is carried adjacent the bottom surface of the piston body.   
     
     
       2. An adjustable damper operable in extension and compression strokes comprising: a tube;   a piston slidably carried within the tube and separating the tube into an extension chamber and a compression chamber with flow passages extending through the piston between the extension and compression chambers;   a single bi-directional passive damping valve positioned on the piston between the extension and compression chambers, the passive damping valve normally substantially closing the flow passages and providing damping during both extension and compression strokes of the damper;   a control valve carried on the piston controlling fluid flow through the piston flow passages and providing a variable amount of damping by regulating damper fluid flow between the extension chamber and the compression chamber of the damper during extension and compression strokes, the control valve including a single movable element in the form of a spool carried in a spool bore with the flow passages through the piston communicating with ports in the control valve wherein flow through the control valve is alternately interrupted and permitted; and   a first electrical coil and a second electrical coil positioned adjacent the spool bore and working in concert providing a selective motive force to selectively position the spool wherein the piston includes a top surface with an annular trough and a bottom surface wherein the flow passages intersect the annular trough and open through the bottom surface and wherein the control valve is positioned against the bottom surface and further comprising a seal positioned radially inside the flow passages at the bottom surface and between the piston and the control valve and wherein damping is controlled solely by the single bi-directional passive damping valve and the spool.